This invention relates to a novel rust preventive coating composition.
Because of their good durability and the lasting anti-corrosive effects of resulting coatings, coating compositions comprising zinc powder have heretofore enjoyed wide use, and the amount of these compositions consumed has been increasing.
As practical uses of these coating compositions, there can be mentioned, for example, coating of bridges, especially long and large bridges, inner coating of tanks of ships and the like, and coating of places and parts where maintenance or repair is difficult.
Further, with a view to avoiding environmental pollution and preventing fire, and to saving labor and protecting workers from the toxic effects of the coating positions, these zinc powder-containing rust preventive coating compositions are being more often applied in the state dissolved in water.
Various methods for water-solubilizing zinc powder-containing coating compositions are known in the art. For instance, two-component type coating compositions comprising zinc powder and an alkali metal silicate have heretofore been put into practical use. However, they are defective in that since hardening is accomplished by an inorganic reaction, the pot life is generally shorter than about 2 hours and the coating operability of the compositions, therefore, is very poor.